A mixture of polypeptides which do not all have the same amino acid sequence referred to as glatiramer acetate (GA) is marketed under the tradename COPAXONE® and comprises the acetate salts of polypeptides containing L-glutamic acid, L-alanine, L-tyrosine and L-lysine at average molar fractions of 0.141, 0.427, 0.095 and 0.338, respectively. The average molecular weight of COPAXONE® is between 4,700 and 11,000 daltons. (“COPAXONE”, Physician's Desk Reference, (2000), Medical Economics Co., Inc., (Montvale, NJ), 3115.) Chemically, glatirarner acetate is designated L-glutamic acid polymer with L-alanine, L-lysine, L-tyrosine, acetate (salt) . Its structural formula is:(Glu, Ala, Lys, Tyr)x•XCH3COOH (C5H9NO4•C3H7NO2•C6H14N2O2•C9H11NO3)x•XC2H4O2 CAS—147245-92-9
(“Copaxone”, Physician's Desk Reference, (2000), Medical Economics Co., Inc., (Montvale, N.J.), 3115.)
Glatiramer acetate is approved for reduction of the frequency of relapses in patients with relapsing-remitting multiple sclerosis. Multiple sclerosis has been classified as an autoimmune disease. Glatiramer acetate has also been disclosed for use in the treatment of other autoimmune diseases (Publication No. U.S. 2002/0055466 A1 for R. Aharoni et al.), inflammatory non-autoimmune diseases (Publication No. U.S. 2005/0014694 A1 for V. Wee Yong et al.; and U.S. Patent Application No. 2002/0077278 A1, published Jun. 20, 2002 (Young et al.)) and to promote nerve regeneration and/or to prevent or inhibit secondary degeneration which may follow primary nervous system injury (Publication No. U.S. 2003/0004099 A1 for M. Eisenbach-Schwartz et al.; and U.S. patent application Ser. No. 2002/0037848 A1, published Mar. 28, 2002 (Eisenbach-Schwartz)). Furthermore, glatiramer acetate has been disclosed as a treatment for immune mediated diseases (e.g., U.S. Pat. No. 6,514,938 B1, issued Feb. 4, 2003 (Gad et al.); PCT International Publication No. WO 01/60392, published Aug. 23, 2001 (Gilbert et al.); and PCT International Publication No. WO 00/27417, published May 19, 2000 (Aharoni et al.) as well as diseases associated with demyelination (PCT International Publication No. WO-1/97846, published Dec. 27, 2001 (Moses et al.).
The manufacturing process as detailed in the above patents involves reacting protected polypeptides with 33% hydrobromic acid in acetic acid. (U.S. Pat. No. 5,800,808, issued Sep. 1, 1998 to Konfino, et al.) This deprotection reaction removes the gamma benzyl protecting group from the 5-carboxylate of the glutamate residue and cleaves the polymer to smaller polypeptides to form a trifluoroacetyl polypeptide. (U.S. Pat. No. 5,800,808, issued Sep. 1, 1998 to Konfino, et al.) The time needed to obtain GA of the proper average molecular weight of between 7,000±2,000 daltons depends on the reaction temperature and the molecular weight profile of the protected glatiramer acetate. (U.S. Pat. No. 5,800,808, issued Sep. 1, 1998 to Konfino, et al.) The deprotection occurs at a temperature of between 20° C. and 28° C. (U.S. Pat. No. 5,800,808, issued Sep. 1, 1998 to Konfino, et al.). A test reaction is performed on every batch at different time periods to determine the reaction time needed at a given temperature to achieve trifluoroacetyl polypeptides of a proper molecular weight profile. (U.S. Pat. No. 5,981,589, issued Nov. 9, 1999 to Konfino, et al.) The amount of time needed for the reaction ranges, for example, between 10 and 50 hours. (U.S. Pat. No. 5,800,808, issued Sep. 1, 1998 to Konfino, et al.). In addition, U.S. Pat. Nos. 5,981,589, 6,048,898, 6,054,430, 6,342,476, 6,362,161, and 6,620,847, also relate to compositions and methods for manufacture of mixtures of polypeptides, including GA.
This invention provides an improved manufacturing process.